Vectors & Scalars

• Scalars are fully defined by magnitude only
  • Distance - this is the distance travelled from A to B
• Vectors have a magnitude and direction
  • May put arrow on top to indicate $\vec{s}$
  • Exceptions do exist if the question asks for the magnitude (understand context of question)
  • Also, if given compass directions, then return in compass directions.
    • Don't write compass directions if they are not explicitly given; for rivers, for example, just write up/downstream if North not given
  • Assume vehicles are moving forward
  • Assume falling objects are going down
• Below is a vector quantity table;

Vector vs Free body diagram

• Free body diagrams show all real forces acting on a body
  • $W$ - weight/gravitational force
  • $Lift$ - lift force
  • $Drag$ - drag force
  • $Thrust$ - thrust force
  • Don't write acceleration - it isn't a force!
  • The diagram is centered on a dot
• Vector diagrams show the resolved vectors acting in a situation
  • Must use arrows (same for FBD)
  • Must have the same vector quantity on each side
  • Must be resolved
  • Define own compass direction (for relevant questions)
  • Head to Tail